The conventional patio doors each include a glass panel in a sash, with at least one door being capable of sliding movement relative to the other within tracks at the top and bottom of the door opening frame.
These patio doors are very appealing, for their ease of opening a relatively large area and for the amount of daylight illumination provided. However, these patio doors are relatively easy to open by unauthorized individuals when provided with a lock. Of course, the underlying assumption for all these lock mechanisms to be effective is that an intruder will never resort to smash the entire glass panel to gain entry into the dwelling, because the noise caused by the blow and falling of glass on the ground would constitute appropriate deterrence for the intruder.
Standard security locks have fingers engageable with selected notches in the top edges of the panels in their closed position, which is secured by an ordinary key-operated cylinder lock. These locks can be forced by the pry of a crowbar or wedge, and can be disengaged by forcing steel chisels through the outer frames at the position of the lock.
In the last decade or so, a number of locking bars have appeared in the field, mounted to the fixed patio door at waist height, for pivotal movement around a pivotal member from an unlocked vertical position to a locked horizontal position. In locked horizontal position, the locking bar effectively prevents opening of the slidable patio door, by extending in between the outer sash of the latter and the opposite door jamb.
These pivotal members for the locking security bars are obviously critical in the efficiency of prevention of unauthorized ingress, but have remained quite primitive in their design. It is believed that some improvement could be brought to such a pivotal member.